Image detection and recognition is an important research field in computer vision. The most common technology in image detection and recognition detects and recognizes an image by extracting features or characteristics from the image.
In the related art, an image is detected and recognized by obtaining (e.g., extracting) the Histogram of Oriented Gradient (HOG) characteristics (or features) of the image. The method to extract the characteristics of HOG is described as follows: computing the gradient of each pixel in an image; dividing the image into a plurality of cells, each cell including a plurality of pixels, and every neighboring n cells forming a block; calculating the Histogram of Gradient of all of the pixels in each cell, and extracting the characteristics of HOG of respective blocks according to the Histogram of Gradient of all of the cells in the block; and extracting the characteristics of HOG of the image according to the statistics of the characteristics of HOG of all the blocks in the image.